As mentioned, this is with selinux-policy-targeted-1.21.16-4. Is there anything
else that would need to be done after setting the boolean? Also, I'm not sure
if this is correct, seems new to me:
[root@hawk targeted]# grep exec bool*
booleans:allow_execmem=0
booleans:allow_execmod=0
booleans:httpd_ssi_exec=1
booleans.local:allow_execmem=1
booleans.local:allow_execmod=1

The problem you have is that you have partially updated to some interim policy,
perhaps and interim policycoreutils and a later kernel. Please get up to date
on your policy, policycoreutils, libselinux, and libsepol.
Load_policy and the rest of selinux now uses booleans.local to override the
defaults in the booleans file. So this looks correct.
Dan